US2629329A - Deep well pump - Google Patents

Description

Feb. 24, 1953 Filed oct. 4, 1946 Feb. 24, 1953 H. E. ROSE ET AL DEEP WELL PUMP Filed OC'C. 4, 1946 2 SHEETS--SHEET 2 Patented Feb. 24, 1953 UNITED STATES PATENT OFFICE DEEP WELL PUMP of Missouri Application October 4, 1946, Serial No. 701,166

(Cl. S-46) 17 Claims.

The present invention relates to a. deep well pumper. That is to say, it has particular advantages in connection with deep well pumping, although it will he understood that its features are applicable to other related operations.

In particular, this pumper is of the type having a pumping mechanism disposed adjacent the bottom of a well and connected by a power oil pipe to the top of the well, inV which the power oil is subjected to pressure that produces a pressure condition at the bottom of the well greater than the column of oil being pumped. This power oil is used to cause operation of the pumping mechanism disposed in the bottom of the Well.

In the present invention, a valving means is provided for controlling the disposition of this power oil upon pumping piston means. In particular, the pumping mechanism comprises a double-acting piston, having two piston heads each operating in a cylinder. The cylinders, on corresponding sides of the two pistons, are alternately subjected to the power oil, so that the two pistons are alternately driven in opposite directions. The corresponding sides of the cylinders on the opposite sides of the pistons are those which alternately draw oil from the Well and eject it into the casing above the pumping mechanism.

It is an object of this invention to provide a valving mechanism for controlling the disposition of the power oil to the pistons alternately, which valving mechanism is reversed by a force produced as the pistons approach the extremes of their strokes. Particularly, it is an object of the invention to provide a valving mechanism which first applies power oil to one piston and lthen to the other, exhausting the power oil previously supplied to said other piston while it is applying power oil to the rst one, and employing pressure developed from the exhausting pressure -oil to reverse the valve mechanism.

it is a further object to employ the foregoing l 'system to act as a dashpot means for the pistons. it is a particular object to provide a pumping device and a reversing valve mechanism that relieves the power substantially concurently with the arrival of the piston at the end of its stroke.

More particularly, it is an object of the invention to employ the exhausting power oil from the exhausting piston to charge areversing pressure chamber on reversing valve mechanism, and then to cause pressure to be applied, through the action ci the piston, to the oil thus charged to the pressure chamber, whereby ,to .reverse the valve mechanism,

A further object of the invention is to provide a dashpot plunger, one end of which is in communication` with the pressure chamber of the reversing valve mechanism, and valve means associated with the dashpot plunger, through which the oil from the exhausting cylinder may charge the pressure chamber, in an arrangement by which the valve is closed by the main piston, and which dashpot plunger is thereafter actuated hy the main piston, so that the entrapped dashpot oil is then caused to be subjected to pressure that actuates the reversing valve.

Further objects include the provision of means to provide complete piston travel before the piston stops. Particularly, it is an object to provide the complete piston travel through the medium of a pilot valve in the reversing valve mechanism.

A further object is to provide valves that are initially loaded so that they will start the mechanism in the right direction.

In the drawings:

Fig. 1 is a broken View of the pumping mechanism, shown in diametric section;

Fig. 2 is an enlarged view in section of one of the dashpot plungers; and

Fig. 3 is a diagrammatic section showing the valve mechanism.

The mechanism may be understood by referring to Fig. 3, wherein the valve mechanism is developed out of circular arrangement. There is a well casing I il. This well casing Il] has a conventional shoe II at its bottom, this shoe being designated diagrammatically in Fig. 3. The shoe has a tapered opening therethrough.

A pumper mechanism comprises a tubular portion I2 having an upper head I3 thereon and a lower head I4 thereon. This lower head is tapered and iits in sealing relation into the tapered opening of the shoe I I. By this means, the pump casing I 2, which is smaller in diameter than the well casing IB, provides a space I5 Within the casing above the shoe, for the reception of the oil that is pumped.

The lower head I4 has a central passage I6 therethrough that communicates With the supply of oil in the well that is to be pumped. This passage I5 connects with an elongated tube or passage I'I that leads up to the upper head I3.

In the upper head I3, the passage I6 connects through a ball check valve or the line I8 with the upper end of an upper cylinder formed by a cylinder wall member I9 that -is attached to the Ahead and is smaller in diameter than the pumper casing I2. The cylinder I9 is connected at its lower end with a valve mechanism housing, generally designated at 2E). The lower end of the valve mechanism housing is connected to a lower cylinder 2I that is attached at its lower end tothe head I4. The tube or passage I'I that leads yinto the head I3 connects across a ball check valve 22 into the lower end of the cylinder 2|.

There is a piston 24 reciprocable within the upper cylinder casing I9. This piston is mounted upon a piston rod 25 that slidably passes through the valve housing 25 into the lower cylinder casing 2I where it supports a second piston 25. The two pistons 24 and 25 thereby reciprocate together in their respective cylinders.

The piston 24 divides the cylinder I9 into opposite chambers. The one above the piston 24 is designated at 28; that below the piston 24 is designated at 29. In like manner, the piston 23 divides its cylinder into an upper chamber and a lower chamber 3I.

The upper chamber 23 of the piston 24 connects through a ball check valve 33 by way of a passage 34 with the space I5 between the well casing I3 and the pump casing I2. In like manner, the lower chamber 3| below the piston 25 connects'across a ball check valve 31 by way of a passage 38 to the space I5.

It may be seen that, when the piston 24 descends, it may open the check valve i8 and close the check valve 33.V Likewise, when the piston 25 ascends, it may open the check valve V22 and close the check valve 31.

The pump pistons are actuated oppositely by Vmeans of power oil. This oil is introduced into the top of the upper head I3 through a passage te. It will be understood that the passage 40 is connected by a pipe to the top of the well where a pressure applying mechanism is disposed to maintain a pressure on the oil column at the bottom of the line 40 that is greater than the head of pressure of the oil column being lifted.

The passage 40 in the head I3 connects by a pipe 4I down into the housing 20 for the valve mechanism. In this housing 2Q, the pipe 4I leads to a mid-portion thereof. This pipe 4I within the valve housing 2D opens directly into a reversing valve cylindrical chamber 43 and is connected by a cross port 44 that, at all times, opens into a pilot valve chamber 45 and a double-acting relief valve cylindrical chamber 4t.

The cylinder 43 receives a reversing valve 48 of the three-land type. The three lands provide an upper valve passage 49Vand a lower valve passage 50. They also provide an upper pressure chamber 5I and a lower pressure chamber 52, to receive uid under pressure for the actuation of the valve 48 either up or down. A coil spring 53 in the lower pressure chamber 52 normally urges the valve upwardly.

The valve chamber 43 has a connection by way of a passage 55 leading through the valve housing 2l! to the piston chamber 29 below the piston 24. It also has a corresponding passage 55 that leads to the chamber 35 above the piston 25. In addition, it has two exhaust passages 5l and 53 that connect with the receiving space I5. It may be seen that, when the valve 48 isY in its indicated position, the pipe 4I is connected 5e by the valve passage 50. It is cut off from the pressure passage 4I by the valve.

The slide valve 48 is adapted to be actuated by power oil applied oppositely to its pressure chambers 5I and 52. This is controlled by a three-land pilot valve 52, that reciprocates within the cylinder 45 in the housing 25.

The three lands provide an upper valve passage 53 and a lower valve passage 64. Above the valve 62, there is a pressure chamber 55, and below it is a pressure chamber 55. A coil spring El normally urges the Valve 52 downwardly.

The cylinder 45 is connected by an upper passage 58 that leads to the pressure chamber 5i of the valve 48. It is likewise connected by a corresponding passage 59 with the lower pressure chamber 52 of the Valve 48. The chamber d5 is also connected toward its opposite ends by ports I6 Yand II with an exhaust passage 12 that constantly opens tov the passage I5. As shown, this passage 'I2 connects with the valve cylinder 45, but is constantly open around the valve therein, as by a groove. The two exhaust ports 'IB and 'II are spaced to be controlled by the end lands of the valve 62. The middle land controls the pressure oil port d4.

The valve 52 is actuated by pressure introduced at its opposite pressure chambers S5 and 66 under control of a four-land double-acting pressure relief valve 'I5 that recprocates in the cylinder 45. The four lands provide an upper valve passage la, a middle pasage 19, and a lower passage 85. Above the Valve 16, there is a pressure chamber 8! and below it a pressure chamber 82.

The valve l5 is shown in a lower position in p Fig. 3. This valve has an extending valve stem projecting into the upper pressure chamber 6I. It has a head Sl at its extreme end. Between the head 3l and the rst land on the valve, there is a coil spring 88 that acts oppositely against two collars 89 and B0, normally urging them apart. A tubular member BI is attached into the valve housing 23, and it has a hollow cap 92. In relieved position, the spring S8 causes the collar 89 to move upwardly to engage the cap 92; and it also urges the collar 90 downwardly to engage the end of the valve housing 25 adjacent the tting of the tube 9i. In this position, the two collars B9 and 9B may be in engagement with the cap 92 and the upper valve land, respectively, and the valve will be yieldably maintained in neutral position. When the valveis moved to the position shown, the spring. is compressed between the collar 9G, which is held against downward movement, and the collar 83 which is forced downwardly. When the valve is moved oppositely from its neutral position,. the upper land will engage the collar 90 and( force it upwardly, while the collar 83 is held by the cap S2. The two collars 89 and 90 are loosely tted in their respective parts, so that uid can flow past them.

The pressure passage 44 connects into the cylinder 46 in the valve passage 'I9 of the valve '16.v The cylinder 46 likewise is connected by a passage 35 to the pressure chamber 35 above the valve 52. The cylinder 46 is likewise connected by a passage 96 with the pressure chamber B5 below the valve 67.. nected to exhaust through the passage l2 at its upper end and a port 91 at its lower end. These two exhaust ports connect into the space I5 within the outer casing I0.

The opposite ends of the valve 'I6 are adapted to be connected, respectively, to the inner cylin- It likewise is conder spaces 29 and 30 of the two pistonsV 2'4. and 26 To this end,` there is an upper' passage |00 leading from. the pressure chamber BI above the valve '|61 and connecting into a dashpot cylinder I'III. This. dashpot cylinder receives a plunger |02 that is ported` at |03 with a control valve It at the top thereof. The details of this. construction will appear hereafter.

In like manner, the lower pressure chamber 82 of the valve I6` is connected by a passage |08 into ay lower dashpot cylinder |09 that receives a dashpot plunger |`|0., controlled by a valve II I, as will appear.

The. construction of the dashpot plunger is as shown. in Fig. 2.. Both of the two dashpot arrangements. that is, the one for the upper piston 2.4 and the lower piston are identical. 2 shows the one for the lower piston.

The main valve housing` 20 is provided with a cylindrical extension ||5 onto which the lower cylinder 2| is secured. The piston rod 25 operatesin a cylindrical passage itil in this extension |15. The extension |I5 also receives the end. of the passage |08 and the cylinder |09.. t A collar l`|8 is sealed into the open end of the cylinder |09.v

The piston IIO. that reciprocates within the cylinder |09 is a composite member. It consists of a sliding plunger head |20 that is prevented from sliding out the end of the cylinder by the collar |18.. It is normally urged by a coil spring I2I toward the collar.

The head |20 receives a threaded projection of a tubular stem. |22 that has a passage |23 therethrough. This stem, in turn, receives a valve housing element |24 thatis threaded in the manner shown to the stern |22. rIhe member |24 providesv a spring` chamber |25 that, in return, has a valve stern |26 operating therein. This valve stem has a flange |21 against which a coil spring |28 acts normally to urge the stein Fig'. 1 is provided. This'showing omits the arrangement of the reversing valve mechanism save for certain parts which indicate how it is assembled into `the pump casing. Fig. i does not show the outer well casing I0.

As shown in Fig. 1, the pump casing I2 is made of several sections. There is an upper section |2a which continues down to the reversing valve mechanism housing to which it is threaded, as indicated in the second column of Fig. 1, A lower pump casing section |217, as shown in the third column of Fig. 1, is threaded onto the bottom of the reversing valve housing 20. The up per head I3 likewise is a composite member. It will be seen from the first column of Figl to be litted into the upper casing element |2a it may be slipped upwardly thereinto from the lower part of the casing'. Above the portion I3@ there isa union member |31) having a head |30 that can be clamped downwardly by a threaded union ring I 3d, against the top of the front main head member I 3a. A spacer ring I3-e' isv passed over the ring I 3d and is surmounted by a union cap |3f with a final nut I 3gv holding the parts to gether.

The tubular connector |31;l contains the upper part a of the pressure passage. `The upper end of the connector |3b is adapted to be connected with a power oil pipe leading to the surface.

The lower member |3c of the upper member I3?) has an enlargement ddh connecting with the passage 40a so that the passage 40a may lead into an oli-center passage section 40e, regardless Y of the angular disposition of the upper connector outwardly. Outside of the tubular element |24 1 is. the valve head ||I which is secured toV the stem` |26. The chamber |25 communicates around the valve stem |26 so that fluid now can take place around the head or the valve and through an axial opening |29, which is of varying diameters, into the spring chamber |25, and thence into the passage l23.to enter the cylinder |00. The valve head is tapered on its innerend and may engage with a sealing ring oi resilient material at |32. `The taper on the valve head spreads this sealing ring outwardly to engage the walls. of the passage |29 andprevent 'the ilow of fluid therethrough. When the valve head I! I is in its. outer position, to which it` is. urged by the coil spring |28. the ring |32 contracts so to permit ther ilow of fluid around it.

The head is positioned to be `engaged by the upper face of the piston 25 when the piston approaches the end `of its stroke. Further movement of the piston 26 will close. the valve I', and thereafter will displace the piston Il upwardly against the spring i2I. This will then displace the liquid entrapped within the. cylinder |09 through the passage Ili` to the lower end of the valve 16, forcing the same upwardly.

In like manner, the'pistcn 24, can strike its valve |04, closing the same, and thereafter displace the piston |02 downwardly. The two piston constructions and their valve arrangements are identical, although the upper one in Fig. 3 is shown diagrammatically.

In order to show how this pump mechanism is arranged for fitting into a well, the showing of |311 relative to the main head` portion Ita.

The pipe #l is connected, as shown in the irst column of Fig. 1, to the lower part of the passage 40e. This pipe leads down to the lower part of the second column of Fig. i, where it is conu nected into the housing 20 for the reversing valve mechanism.

The upper head member I3 is connected to the cylinder I9 that is smaller than the pumpV casing I2. Ille cylinder I9 is, inturn, connected with an extension H5 of the housing 2i), as shown in the first two columns of Fig. 1,. and particularly the second one.

The lower head I4 comprises a bottom section Ma' and is threaded into the bottom of the pumper casing E212, shown in the fourth column of Fig. l. It interts with a second head member labthat has. a head received in a recess of a third head portion Mc. The lower cylinder 2| is attached to the head member lf'lc. The: cylinder 2| extends.,upwardly and is united at its top to the extension H5 that, at its upper end', is secured to the valve housing 20.

The lower head portion I4 has the inlet passage |6 therethrough. This inlet passage is continued at |617` in the head member Ifb, through the enlargement idc into the passage ld in the head member Ific. It opens at I te into the lower space lla above the head Ido of the passage designated Il in Fig. 3.

The housing 20 has an arcuate passage Ill) therethrough. This connects at its bottom with the space Ita and at its top with a similar space |10. The space ile is `formed within the upper pump casing Ia, which also contains the cylinderv ES and the pipe I, but ports ample space for the passage` of oil upwardly;

The passage lee, in the bottom of the pump, opens through the check valve 22', shown in dote ted lines at the upper part of the fourth celumn of Figfl, into the passage 38' above the checlr valve 3l, which'ls the equivalent of the-strucw ture shown in Fig. 1. At the upper end of .the space Ic, there is a connection through the check valve I8, shown in dotted lines at the bottom of the first column of Fig. l, into the passage 34 that opens downwardly into the interior of the cylinder i9.

The upper piston 24 appears in the second column of Fig. 1, and it is attached by the piston rod 25 with the lower piston 25. The chambers 28 and 29 appear in the second column above and below the piston 24, and the chambers 38 and 3| appear inthe third and fourth columns above and below the piston 26.

The extension 9| and cap 92 of the reversing valve mechanism appear above the middle of the third column of Fig. 1. They are here shown as connected into the bottom of the valve housing 233. This is the equivalent structure of that shown in Fig. 3, wherein these parts are Vshown as connected into the top of the valve housing. Adjacent them is an extension 53a to hold the spring 53 of the reversing valve.

The cylinder chamber 29 below the upper pis-I ton 24 contains the upper dashpot plunger |32 that operates in the upper extension H5 of the ered until the lower head i4 seats sealingly with the shoe I l. The passage IS will thereby be introduced into the oil supply. Power oil is filled into the pipe 4|).

At the start, the reversing valve mechanism has the directional valve 48 in its upper position under the inuence of the spring 53. The pilot valve 62 is in its lower position under the iniiuence of the spring 61. The relief valve is in a neutral position under the influence of its Ybalancing spring 83.

Power oil will flow through the passage 45 and the passage 4| to the cylinder 43 of the .reversing valve and the cross passage 44, from which latter it communicates into the two cylinders 45 Y and 45.

With the reversing valve 48 upwardly undner the influence of its spring 53, this power oil may now through the valve passage 5i) and the passage 55 to the cylinder 3E) above the piston 25,

Also, with the pilot valve downwardly under the influence of its spring B7, power oil may flow through the passage 44 and the upper valve passage 63 of the pilot valve to the passage 5i! leading into the pressurechamber 5| abovethe directional valve 48. The lower pressure chamber 52 below the reversing va1ve'48 is connected `to Y exhaust when the pilot valve 62 is down, because the passageway 69 connects through the lower passage 64 of the pilot valve 62 with the exhaust passage that leads to the space I5. lThe directional valve will be forced downwardly when the pressure differential between the chambers 5| and 52 produces a force greater than that ofV the spring 53. n

When the directional valve is up, porting power oil to the pump cylinder 30, the pressure in the upper directional valve chamber is insufficient to Y overcome the spring 53. Hence power oil is ported by the directional valve intothe 4cylinder 3E! until that cylinder is lled and its piston. 26 is down. When that condition is reached, the power oil will build up pressure in the upper directional valve chamber 5|, and the directional valve will be forced down against Ythe spring 53. The spring 53 is thus strong enough to resist valve movement under power oil pressure when the piston is movable, even though there be Zero head of oil in the chamber 52.

TheY lowering of the directional valve 4S introduces the power oil from the pipe di through the valve passage and the passage 55 to the charnber 29 below the upper piston 24. At the same time, it ports the chamber 30 above the piston 26 to exhaust into the casing space i5 through the passage 55, the valve passage 5,0, and the exhaust passage 58. Y

The introduction of power oil to the chamber 2Q below the piston 24 causes this piston to rise and the piston 26 to'rise with it. Elevation of the piston 214 first opens the valve maand then permits the plunger 'i132 to be elevated by its spring |2|. Oil may then charge 'the upper dashpo-t system. The valve 'i6 is thereby subjected at its top to pressure oil and at its bottom to oil at the pressure produced by the head in the casing space i5. This pressure differential, even with zero casing level head, is insufcient to overcome the force of the spring, and the double-acting valve 'i6 remains in its neutral position. Even if the foregoing Vwere to shift the valve 16, no change would follow, as the valve would be lowered, porting pressure oil to the top chamber 65 of the pilot valve. The spring 5l has already lowered this pilot valve, so no shift occurs if the foregoing takes place.

As the piston V26 rises towardrthe end of its stroke, it strikes the head of the lower dashpot plunger il, causing this valve toY close, trapping the oil above the valve containedwithin the cylinder |59, the chamber 32, and the associated passages. This entrapped` oil thereupon constitutes a substantially inelastic connection between the piston 26 and the 'lower end of the double-acting relier" valve l5. movement of the piston 26 by the actionrof the pressure oil below the upper piston 24 will cause 'the entire plunger i@ to be forced upwardly against the spring |2|. This action applies pressure to the entrapped oil acting within thelower chamber 82 of the double-acting relief valve, and the continued upward movement of the piston thereby causes the double-acting relief valve to move upwardly against the spring Sii. In the upward movement of the valve 'i5 under force from the piston 2t acting through the conn necting entrappedoil, the upper end of the valve 76 can expel oil from the chamber 3i and connected spaces, through the passage iiii, and out past the valve |04 that is at such time open. There is a dashpot eiiect in this action of the valve 16.

It will be understood that, during the upward travel of the piston 25, oil is sucked in from the well Vthrough the lower passage It and past the check valve 22, this suction maintaining the valve 31 closed. Thus, the lower cylinder 3| is charged with new oil.

The elevating of the double-acting ,relief valve in the manner aforesaid introduces pressure oil from theY passage 44 to the passage EDS, which is now connected to the valve passageV 'l between the two middle lands of the double-acting-valve.

Continued upwardV This pressure oil, acting through the passage 96, is delivered to the lower pressure chamber 66 of the pilot valve 62, At the same time', the upper chamber 65, which contains the spring 61, is ported through the passage 95 to exhaust by the upward movement of the double-acting relief valve which connects the outlet of the passage 95 with the exhaust passage 91. Thus the pilot valve is moved upwardly `by this shift.

When the pilot valve `moves upwardly, it con.- nects the pressure oil from the passage 44 to the valve passage 64 with the line 69 leading to the lower pressure chamber 52 below the reversing valve. At the same time, it ports the upper chamber l above the reversing 4valve through the passage Gt with exhaust by -way of the valve passage 63 and the exhaust Apassages 1U and 12. Meanwhile the exhaust lpassage 1i is cut off by the bottom land of the valve B2.

The reversing valve is, lby the foregoing action, moved upwardly. As will be understood, this shifting of the reversing valve cuts the cylinder 29 below the piston 24 to exhaust by way of the valve passage 49 and the exhaust passage 51, so that this pressure oil may enter the space l5. It also cuts the pressure oil through the lower passage 59 of the reversing `valve into the passage 56 that leads to the chamber 39 above the piston 26.

The foregoing action produces a quick reversal of the pressure acting in Vthe cylinders y29 and 30. At the end of the power stroke, the power is thus cut olf and reversed, so that impacting of the moving pistons upon the fixed parts is at least greatly reduced. i

When the valves have reversed, Vthe power oil is directed into the cylinder 39 to drive the piston 26 down, carrying the piston 24 with it. Loweringof the piston 26 drives the fresh oil sucked from the well into the pumping cylinder 3l, out past the valve 31 into the casing space l5. At the same time, the `upper piston 24 sucks new oil into the top cylinder 23, past the valve i8.

When `the piston 26 is lowered a short distance, the `plunger' lill is "returned to `starting Vposition and the `valve il I opened, `for release of pressure in the double-acting val-ve chamber 82. With both valves HB4 and III open, `the net pressure differential acting upon the valve 16, `in its valve chambers 3l and `B2, again reduces until it is insuiiicient to overcome `the `spring 88, it being noted that the oil acting `about the spring and associated parts produces forces that balance` except for that upon `the head of the valve. The valve 16 returns to neutral position, trapping the pressure positioning the pilot valve and holding that valve in its set position until the relief valve is later moved oppositely from neutral position by the action of the upper plunger |02 depressed by the upper piston 24 toward the end of the downstroke.

The foregoingcycle will repeat itself automatically, each stroke delivering fresh oil to the casing space I5.

The relief valve spring 88 is calibrated to suit the conditions of the well `wherein the pump `is used. After the casing has been lled with oil, `this 'valve is subjected to casing head pressure at one end and power oil pressure at the other, which is a minimum differential.

is subjected at one end to power oil pressure 4and at its other end to zero gauge pressure. The spring must be strong enough-to resist movement under this maximumfdifferential. It is designed How ever, at the start, with a dry casing, this valve to permit movement only when the greater force produced by the dashpot plunger is applied to it. This force is a function of the area of the pistons 24 and 26 to the area of the plungers |02 and H0. This spring may be regulated to the well The pilot and directional valves are oppositely spring loaded to assure that the pump will start properly and not hang up, either in a dry casing or in one containing a head of oil. Relief of the i :directional valve were operated directly by the relief valve, the directional valve might be cracked open in a reversing direction, and the piston reversed to release the relief valve back to neutral before the directional valve is fully open. A slow pump stroke, or even a block, could result.

not neutralize until the directional valve moves. ,Hence the pilot valve must reverse at least partially before the relief valve neutralizes, and the directional valve is assured of a complete, if delayed, full stroke. The pump will thus be assured of receiving full pressure of the power oil for each stroke.

What is claimed is:

l. A mechanism of the kind described, cornprising a cylinder means, piston means operated therein by pressure differential in the cylinder meanson opposite sides thereof, a iiuid pressure line, valve mechanism movable from a position connecting the hline to the cylinder means for admitting pressure from the line to the cylinder means to eifect movement of the piston means,

to a position relieving the said cylinder means from said pressure that produces movement, fluid pressure-,responsive mechanism movable to operate the valve mechanism Vto relieving position, movable means operated by the piston means as it approaches the end of its stroke, to producel la pressure that actuates the fluid pressureresponsive mechanism, said last means includ` ing a plunger engageable by the piston means,V

a liuid cylinder in which the plunger is movable, and spring means opposing movement of the plunger by the piston means.

2. A mechanism of the kind described, coniprising a cylinder means, piston means operated therein by pressure differential `in the cylinder means on opposite sides thereof, a fiuid pressure line, valve mechanism movable from a position connecting the line to the cylinder means forV admitting pressure from the line to the cylinderof the piston means,-

means to effect movement to a position relieving Vthe said cylinder means fromsaid pressure that produces movement, fluid pressure-responsive mechanism movable to operate the valve mechanism to relieving position, movable `means operated `by the piston means as it approaches the end of its stroke, to produce a pressure that actuantes ,the fluid pressure-responsive mechanism, Said last means including a plunger engageableby thepiston means, va fluidv cylinder in which the plungeris movable, anda valve between the fluid cylinder `and the cylinder' depth, as power oil pressure is a function there- The present arrangement avoids this. The pilot valve must shaft partially before `the directional valve can move. The relief valve canmeans, the valve being closed upon operation oi the plunger by the piston means.

3. A mechanism of the kind described, comprising a pair of cylinders, a pair of connected pistons, one in each cylinder, a reversing valve mechanism for connecting the cylinders alternately to a huid pressure source, the reversing valve mechanism including a reversing directional valve, and fluid pressure-responsive means for actuating the same to each of its positions, the last means including opposite fluid. pressure chambers and mechanism operated thereby to control operation of the valve, a movable wall means closing each fluid pressure chamber and engageable by Veach piston atthe latter end of its stroke, each wall means being adapted to reduce the capacity of one uid pressure chamber and thereby produce fluid pressure therein, whereby the fluid pressure-responsive means may be operated to reverse the directional valve.

4. A mechanism of the kind described, comprising a pair of cylinders, a pair of connected pistons, one in each cylinder, a reversing` valve mechanism for connecting the cylinders alternately to a fluid pressure source, the reversing valve mechanism including a reversing directional valve, and fluid pressure-responsive means for actuating the same to each of itsl positions, said last means including a pair of uid containing chambers, a movable wall for each chamber and in each cylinder, one movable wall being engageable by each piston and moved thereby at the end of the piston stroke, to produce pressure in its chamber to actuate the fluid pressureresponsive means and effect reversal of the directional valve.

5. A mechanism of the kind described, comprising a pair of cylinders, a pair of connected pistons, one in each cylinder, a reversing valve mechanism for connecting the cylinders alternately to a fluid pressure source, the reversing valve mechanism including a reversing directional valve, opposite pressure chambers associated with the directional valve adapted to receive fluid under pressure for oppositely shifting the valve, means for porting fluid pressure alternatively into the chambers, including a double-acting relief valve normally yieldably maintained in neutral position, additional opposite pressure chambers for Yreceiving pressure uid for oppositely displacing the relief valve from neutral position, a movable wall in each additional chamber, each wall being displaced by movement of one piston at the end of its stroke,

for applying pressure in its pressure chamber to displace the relief valve and eiect reversal of the directional valve. l

6. A mechanism of the kind described, comprising a pair of cylinders, a pair of connected pistons, one in each cylinder, a reversing valve mechanism for connecting the cylinders alternately to a fluid pressure source, the reversing valve mechanism including a reversing directional Y valve, opposite pressure chambers associated with the directional valve adapted to receive iluid under pressure for oppositely shifting the valve, means for porting fluid pressure alternatively into the chambers, including a double-acting relief valve normally yieldably maintained in neutral position, additional opposite pressure chambers for receiving pressure fluid for oppositely displacing the relief valve from neutral position, a movable Wall in each additional chamber, each wall being displaced by movement of one piston at the end of its stroke, for applying pressure in its pressure chamber to displace the relief valve and effect reversal of the directional valve, and the porting means including a pilot valve between the relief valve and the directional valve, the relief valve being adapted to effect shifting of the pilot valve, and the pilot valve effecting the porting of fluid to the chambers of the directional valve.

7. A mechanism of the kind described, comprising a pair of cylinders, a pair of connected pistons, one in each cylinder, a reversing valve mechanism for connecting the cylinders alternately to a fluid pressure Source, the reversing Valve mechanism including a reversing directional valve, opposite pressure chambers associated with the directional valve adapted to receive iiuid under pressure for oppositely shifting the valve, means for porting uuid pressure alternatively into the chambers, including a double-acting relief valve normally yieldably maintained in neutral position, additional opposite pressure chambers for receiving pressure uid for oppositely displacing the relief valve from neutral position, a movable wall in each additional chamber, each Wall being displaced by movement of one piston at the end of its stroke, for applying pressure in its pressure chamber to displace the relief valve and effect reversal of the directional valve, and the porting means including a pilot valve between the relief valve and the directional valve, the relief valve being adapted to effect shiftingY of the pilot valve, and the pilot valve effecting the porting of fluid to the chambers of the directional valve, means normally urging Vthe pilot valve into a position to port the pressure uid to displace the directional valve to one position, and means normally urging the directional valve into its opposite position.

8. A fluid pressure mechanism including a cylinder, a piston, a valve to control admission of fluid to the cylinder to act upon the piston, a pressure operated device for controlling actuation of the valve, including a pressure chamber, a plunger movable to vary the size of the chamber and produce lluid pressure conditions, a passage through the plunger, a Valve operable to open and close the passage, the valve being supported on the plunger for engagement by the piston, whereby movement of the piston may close the valve, and the plunger being thereafter displaceable by further movement of the piston.

9. A fluid pressure mechanism including a cylinder, a piston, a valve to control admission of fluid to the cylinder to act upon the piston, a pressure operated device for controlling actuation of the valve, including a pressure chamber, -a plunger movable to vary the size of the chamber and produce fluid pressure conditions, a passage v through the plunger, a valve operable to open Y and close the passage, the valve being supported on the plunger for engagement by the piston, whereby movement of the piston may close the valve, and the plunger being thereafter displaceable by further movement of the piston, and

spring means between the valve andthe ,plunger Y through the plunger, a valve operable to open and close the passage, the valve being supported on "l the plunger for engagement by the pisto n ,rwhere` by movement of the piston may close the valve,"

ricca-'sea i3 and the plunger being thereafter -displaceable by further movement of the piston, and spring means acting on the plunger in opposition to the force of the piston thereon.

il. A pumping mechanism including two cylinders, a pair of pistons, one in each cylinder, connecting means joining the two pistons, being connected to one piston face of each piston, the pistons dividing their cylinders into `two cylindnical spaces in each cylinder, the two spaces through which the connecting means extends being designated inner cylinders, and the two such spaces on the opposite sides of the two pistons being designated outer cylinders, there being liquid inlet passages from the bottom of the pump to the said outer cylinders and liquid outlet passages from said outer cylinders, a power liquid line adapted to contain liquid under pressure, reversing valve mechanism including a housing between the cylinders, :a passage in the housing connected to the power line, a directional valve, each inner cylinder having -a first passage connecting it with the directional valve and an eX- haust passage, the directional valve being movable to connect the power passage with the firs-t passage of one inner lcylinder and to connect the other inner cylinder with its `exhaust passage, and vice versa, a pair of opposite pressure chambers for the directional valve, spring means normally urging the directional valve into one position, a pilot valve in the housing movable to connect one of said pressure chambers of the directional valve with the power passage and the other with the receiving conduit, and vice vers-a, opposite pressure chambers for the pilot valve, spring means normally urging the pilot valve to a position to port pressure liquid to the directional valve to move it :against its spring, the directional valve spring having a strength, and being adapted to hold the directional valve against such movement, so that pressure liquid may be ported thro-ugh the directional valve to a piston, until the piston is in :an extreme position and pressure is thereafter built up in the power passage, and ported through the pilot valve to shift the directional valve, a doubleacting` relief valve in the housing, movable to connect either pilot pressure chamber to the power passage and the other to the receiving conduit, means normally yieldably maintaining the relief valve in neutral position wherein liquid is trapped in the pilot valve pressure chambers, a pair of opposite pressure chambers for the relief valve, one connected to each inner power cylinder, a plunger projecting into each inner cylinder and each said relief valve pressure chamber connections, and engageable by the piston insuch cylinder to be displaced thereby and to build up pressure in the pressure chamber to displace the relief valve,'reverse its connections with the Ypilot valve chambers, shift the pilot valve, and thereby effect shifting of the directional valve to reverse the pistons.

12. in a mechanism of the kind described, a cylinder, -a piston in the cylinder having first means -to operate it in one direction, fluid pressure means for operating it in the other direction, valve mechanism operable to connect the cylinder to fluid under pressure as the piston approaches the end of its stroke by said first means, said valve mechanism .including a uid pressure operated Valve having a pressure chamber connected with the cylinder, a displacement member in the chamber and operable by the piston as the piston approaches the end of its stroke produced by said `first means, a vsecond valve associated with the pressure chamber to admit Vfluid from the cylinder lto the chamber when the second valve is open, and the second valve being arranged to 'be closed when the `piston operates the displacement member to trap the fluid in the chamber, the trapped fluid constituting a connecting means :between the vpiston :and the fluid pressure operated valve, that is displaced by the displacement member in its movement 'by the piston, Ito move the iluid pressure `operated valve, and means V'operable upon movement of the fluid pressure operated valve .as aforesaid., to admit fiuid tothe cylinder to operate the pis-ton in its other direction.

13,. in a mechanism of the kind `described, a cylinder, :a 'piston Tin the cylinder having first means to "operate itin one direction, fluid pressure .means for `opor-ating it vin the other direction, 'valve mechanism operable to connect the cylinder to iiuid Vunder pressure as the piston approaches the end :of its stroke by said first means, said Vvalve mechanism 'including la fluid `pressure operated valve having 'a pressure chamber connected iwi-th the cylinder, 'a Vdisplacement member :in the chamber :and operable by the `piston as the piston approaches jthe end of its stroke produced by said iii-st means, :a second valve associated with the pressure chamber to admit iiuid from the cylinder to the chamber when the :second valve is open, `and the second valve being arranged to be .closed when *the piston operates the displacement member to trap the fluid in the chamber, the trapped fluid constituting a connecting means between :the piston and the fluid pressure operated valve, that fis displaced by the displacement :member inits `movement by the piston, to move the fluid pressure operated valve, means operable upon `movement of the fluid pressure operated valve fas aforesaid, to admit fluid to `the cylinder to operate the piston in its other direction, and means normally urging the seco-ndvalve -to open position.

A14. In va mechanism of `the kind described, a cylinder, piston in the cylinder having first means to operate it .in lone direction, fluid rpressure means for operating it .in the other direction, valve mechanism operable to connect the cylinder to lfluid under pressure 4as the ,piston approaches the end :of :its strokeby said first means, said "valve mechanism including a fluid pressure operated valvehavinga pressure chamber connected with `the cylinder, a displacement member in the chamber `and `operable by the .piston .as 'the piston approaches the end of its stroke produced by :said first means, a second valve associated with the pressure chamber to admit fluid from the cylinder to the chamber when the second valve is open, and the second Valve being arranged to Abe closed when the pis'- ton operates the displacement member to trap the fluid in the chamber, the trapped fluid constituting a connecting means between the piston and the fluid pressure operated valve, that is displaced by the displacement member in its movement by the piston, to move the uid pressure operated valve, and means operable upon movement of the fluid pressure operated valve as aforesaid, to admit fluid to the cylinder to operate the piston in its other direction, the displacement member comprising a plunger projecting into the cylinder in the path of the piston, having sliding engagement with the Walls of the chamber, and having a passage therethrough connecting the chamber and the cylinsagesse i i5" der, the second valve being mounted on the displacement member to close the passage, and having a part projecting into the path of the piston to be engaged thereby in the piston movement aforesaid, so that the piston can close the valve and then move the displacement member. 15. In a mechanism of the kind described, a pair of connected cylinders, a pair of connected pistons operating in the respective cylinders4 for reciprocation together, mechanism to admit iluid under pressure to the first cylinder to act upon the first piston to displace the two pistons in one direction, and to admit iiuid under pressure to the second cylinder to act upon the second piston to displace the two pistons in the opposite direction, said mechanism including a fluid pressure operated valve having opposite fluid chambers for its opposite displacement, each chamber being connected with one of the cylinders, a plunger in each chamber, projecting into its cylinder to be engaged by its piston toward the end of the stroke thereof and displaced thereby, second valve means to close each chamber from its cylinder, arranged to be closed when the piston in such cylinder displaces its plunger, and toV be opened at vother times to admit fluid to the chamber, closure of the second valve trapping the fluid in the chamber so that movement of the piston at the end of its stroke displaces fluid in the chamber to move the fluid pressure operated valve, means operated by the movement of the fluid pressure operated valve by one piston, as aforesaid, to relieve iiuid pressure from the cylinder theretofore receiving pressure, and to admit fluid pressure to the other cylinder.

16. In a mechaism of the kind described, a pair of connected cylinders, a pair of connected pistons operating in the respective cylinders for reciprocation together, mechanism to admit fluid under pressure to the rst cylinder to act upon the rst piston to displace the two pistons in one direction, and to admit fluid under pressure to the second cylinder to act upon the second piston to displace the two pistons in the opposite direction, said mechanism including a fluid pressure operated valve having opposite fluid chambers for its opposite displacement, each chamber being connected with one of the cylinders, a. plunger in each chamber, projecting into its cylinder to be engaged by its piston toward the end of the Ystroke thereof and displaced thereby, second valve means to close each chamber from its cylinder, arranged to be closed when the piston in such cylinder displaces its plunger, and to be opened at other times to admit fluid to the chamber, closure of the second valve trapping the uid in the chamber, so that movement ofthe piston at the end of its stroke displaces fluid in the chamber to move the fluid pressure operated valve, means opi6 erated by the movement of the fluid pressure operated valve by one piston, as aforesaid, to relieve uid pressure from the cylinder theretofore receiving pressure, and to admit fluid pressure to the other cylinder, said last-named means including a directional valve, and opposite fluid pressure chambers to operate it, said uid pressure chambers of the directional valve being connected to pressure and exhaust respectively, by the displacement of the firstnamed fluid pressure operated valve in the manner aforesaid.

17. In a mechanism of the kind described, a cylinder, a piston oppositely movable therein, means for moving the piston in one direction, fluid pressure means for operating it in the other direction, mechanism for controlling admission of fluid pressure to the cylinder. to admit the same for fluid pressure operation of the piston and to exhaust it for operation of the piston by the first-named moving means, said mechanism including a directional valve displaceable to admit fluid to the cylinder and to exhaust the same, fluid pressure chambers at opposite ends of the directional valve to operate it by fluid pressure, means including a relief valve `normally yieldably maintained in neutral position, movable in one direction therefrom to admit fluid pressure to one fluid pressure chamber of the directional valve and in the opposite direction to admit fluid to the other chamber thereof, force transmitting means to connect the relief valve to the piston when the piston approaohes the end of its stroke by the first piston moving means, to cause the piston to shift the relief valve from neutral position to admit fluid pressure to the directional valve to shift it to admit fluid pressure to the cylinder, and force transmitting means to connect the relief valve to the piston when the piston approaches the end of its fluid pressure stroke, to cause the piston to shift the relief valve oppositely and effect relief of pressure within the cylinder, the relief valve having means returning it 4to neutral position when the piston is not at an extreme position, and having means closing both fluid pressure chambers when in said position.

HOWARD E. ROSE. FRANKLIN M. MACDOUGALL. ROGER W. SCHOEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 260,398 Jenkins July 4, 1882 1,907,951 Gage May 9, 1933 0 V2,069,122 Weaver Jan. 26, 1937 2,239,727 Mayer Apr. 29, 1941

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